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MG Midget and Sprite Technical - 1500 inlet port spacing

Hi folks, long time no see. Hope you are all well.

Does anyone have a 1500 head knocking about that they can measure up for me with a digi' caliper?

I am looking for dimensions A and B, the inlet port spacing.

It would obviously be easier to measure C and D and I can work out A and B as I know the ports are 1.25".

Thanks in anticipation.

Malc.

Malcolm Le Chevalier

Hi Malcolm,

Just unwrapped my spare engine, still wrapped up in cling film due to the house move.
dimension A = 0.588 inches
dimension B = 3.522 inches

the head was not clean and the ports were still sooted up and I was using my cheap Ebay calipers.

HTH
Alan
A Pritchett

Alan

Those dimensions seem a bit on the small side. Are they ‘C’ and ‘D’?
Dave O'Neill 2

Thanks Alan,

I assume you mean C and D. :-)

Also, if your inlet ports are sooted up, you have your engine wired up backwards! :-D
Malcolm Le Chevalier

Oops, a deliberate mistake!

the inlets ports have a nice coating of something which will affect the measurement, it is an engine of unknown history and sits under the bench getting in the way.
A Pritchett

Thanks Alan.

So assuming they were working in fractional inch, not decimal, spacing appears to be A = 1 13/16" and B = 4 3/4".

Anyone able to corroborate?

Thanks.
Malc.
Malcolm Le Chevalier

Slightly coked head, coke scraped off prior to reading. Electronic M&W micrometer.
D: 3.503 inches
C: 0.555 inches

I hope that helps, rather than confuse(!)
J Thomson

Thanks J. Much appreciated.

Malcolm Le Chevalier

To respond more fully now I have more time:

I have a gasket on my desk which I tried to measure but couldn't decide if "A" was 1.8" or 1.8125" (1 13/16). I even 3D printed two templates to lay over the gasket to see which looked right and concluded about 51% in favour of it being 1.8". The bore and stroke, for instance, are in decimal inch so I convinced myself the port spacing could/should be too.

Alans measurements swayed me slightly towards it being 1 13/16 instead, but then J has swung it back to 1.8!

I wanted the measurement as I am going to get some flanges made for a custom manifold. I am sure the 0.0125" won't make all that much difference in the grand scheme of things, but it would be nice to get it spot on!

Thanks all,
Malc.

Malcolm Le Chevalier

It's Hubble all over again!
Nigel Atkins

You are always welcome to come up and measure the heads we have up here Malcolm
Peter
Peter Burgess Tuning

You're not thinking of the apertures in doughnuts are you Peter. :)
Nigel Atkins

Nice clean 1500 head

A = 1.810

B = 4.760

Inlet port diameter = 1.245
Chris at Octarine Services

Thanks Peter and Chris :-)
Malcolm Le Chevalier

Mmmmmmmmmmmmmmmm donuts :)
Peter Burgess Tuning

This thread was discussed between 06/09/2019 and 11/09/2019

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